1. Field of the Invention
The present invention relates to a data display apparatus, method and program for displaying, on a display screen, plural datasets each composed of a set of pieces of numerical value data respectively corresponding to plural values on a variable axis that is common to the plural datasets, and also to a data structure for defining display of the plural datasets on a display screen and a recording medium.
2. Description of the Related Art
When a dataset composed of a set of pieces of numerical value data respectively corresponding to plural values on a variable axis is displayed on a display of a computer, and a fluctuation of the numerical value data with respect to the variable axis is observed, it is possible to more easily and visually recognize the fluctuation by displaying the dataset in a graph mode, such as a line chart, a scatter plot and a bar graph, than by displaying a list of numerical value data in a table mode. Therefore, display of datasets in a graph mode is widely used (please refer to Japanese Unexamined Patent Publication No. 6 (1994)-083880 (Patent Document 1)).
However, display in a graph mode ordinarily needs a larger display area than display in a table mode. Therefore, when there are many data series to be displayed, and all of them are tried to be displayed in a graph mode, some data series are not displayed on the same display screen because the display screen is not large enough, and the characteristic of viewing all data at the same time is damaged. In such a case, the data series that are not displayed may be displayed on the display screen by scrolling the display screen, or by limiting the number of data series displayed on the display screen by switching display/non-display setting for each data series. However, the problem of damaging the characteristic of viewing data at the same time is not solved.
As another approach, plural data series may be superimposed one on another, and displayed in the same graph display area. However, in such a case, there is a problem that it becomes difficult to read each graph as the number of data series superimposed one on another is larger.
Alternatively, display in a table mode, in which many data series can be displayed on the same display screen, may be adopted as basic display, and only a part of the displayed data specified by a user may be displayed in a graph mode in a different display area (a display area different from a display area for a table mode) on the display screen. In such a case, it is possible to obtain the merits of making data series of interest easily recognizable by use of a graph or graphs for the part of data series while many data series are displayed on the display screen.